Integrated circuits or "dice" are of such a small size that direct connection of the electrical connection "pads" to other circuitry is impractical. Accordingly, integrated circuits are housed in a larger device known as a "package" which contains conductive leads for providing electrical connections to the integrated circuit bonding pads.
Topology and manufacturing requirements for the conductive leads and other connections to the integrated circuit typically require that the package contain several overlying layers having conductive lines. To preserve the desired functionality of the device, these layers must be electrically insulated from one another. Typically, a layer of solid material such as a plastic, ceramic or glass has been provided between the layers to electrically insulate the layers from one another.
Such a previous configuration is depicted in U.S. Pat. No. 3,676,748 issued July 11, 1972 to Kobayashi et al. Kobayashi et al. also disclose providing two layers of leads located on different stepped planes, formed by using lead frames vertically spaced and insulated from each other.